Almost a Pit

[Fred Mc]

When I built my pole barn 15 years ago I wanted to put in a pit for the bus. However I let the contractor talk me out of it because it would require engineering etc. Instead we left a cutout in the concrete floor for a "future pit"

Every once in a while I get excited about completing this pit. I've thought about a full pit, a 2 foot pit, a 4 foot pit etc. The problem is how to go about construction of this without compromising the existing floor. It also have to be strong enough to support the bus.

Any thoughts on how I might do this.

thanks

Fred Mc. 

[Nick Badame Refrig/ACC]

Hi Fred,

I would cut out your existing hole and dig out how deep you would like it. Then, dig under the existing slab 8" all the way around.

Then pour a cement floor. Then, construct a wooden form 4" smaller then the cut out in your slab. Fill with rebar and cement. Remove the form

and the new concrete will be filled under the existing slab as well as 4" beond the cut out.  Reinforced floor and pit!

Good Luck
Nick-

[Jerry32]

sounds like a PITA but excavating and then pouring concrete footings and walls will just be a little more time consuming but well worth it. I wish I had put in a pit in my place when I had it built but it will never happen now. Jerry

[kyle4501]

I'd evaluate your needs for the pit to determine the depth required. I'm leaning towards a 2 foot deep pit & using a reclining creeper. Of course, if I win the power ball, I'll do the deep pit with a bottom that adjusts to the required height for the job at hand & flush with the floor when not in use  Hey, I can dream, can't I?

The soil conditions will dictate what is required for support while diging. If it is loose sand . . .

However, if it is hard pack, you can probably go as deep as you need.

Anyway, I'd pour a footer & build the walls (I dry stacked block & epoxied rebar into the footer & solid filled all the cells for the base wall for my shop). Once the walls are up, then pour the floor so it will help hold the base of the walls in place. A structural steel angle around the top may be of benefit too.

[Len Silva]

Kind of hard to do after the fact.  When I built mine I had the contractor place air, electric and sump pipes in.  It is 3'-6" wide and 5' deep with a 1-1/2" x 3" lip all around so I can use 4x8 sheets of plywood as a cover.

[HB of CJ]

Nick and Len have it right!   Thanks everyone!  Yeah, go for the full deal, you will find all sorts of neat things you can work on besides your coach.  Make it extra deep and be sure to make plans for the pit side wall mounts sossss you can rig cribbing or steps to step upon to customize the required height sooos you can inspect your Spicer 1710 U-joints and zerk your zerks and stuff like that.   

[Hi yo silver]

In considering the corrosive nature of the concrete, it seems like it would be a good idea to use pvc lines where they will penetrate or be buried in the concrete.  I know with copper gas lines, codes usually require they be run through a plastic sleeve to prevent corrosion. FWIW
Dennis

[jackhartjr]

Please keep in mind the TREMENDOUS power of dirt and/or water!
Case in point; In LaFayette, LA many years ago was a 70 foot long pit for trucks at an old truck stop.  (76 Truck Stop it was, the one that went out of business because they thought they were the greatest and were charging more for everything!  Guess what they weren't and went out of business.)  Anyway the ground started pressing against the sides.  (Or maybe it was a mixture of the ground and water.)  One time I went in and they had welded 12 inch I beam severy 10 or so feet along the top edge.  After awhile even that would not hold and they had to fill it in.  Sooo...the lesson is that if you live in areas where the soil is not compacted, be carefull.
For what it's worth!
Jack

[Dreamscape]

Another idea is to have guide rails on both sides of pit. Might help when driving over. I worked for a fast lube place for a while and that's what they had. Thought that was a safe idea.

Paul